The present invention relates to a device, an application of this device, and a method using this device, allowing measurements and/or interventions to be made in a well at the level of the surrounding formations.
The invention is particularly applicable when measurements and/or interventions are to be made in geological formations traversed by a well. In this case, the measurements carried out may include recording the well-bottom pressure and temperature, measurement (focussed or unfocussed) of the electrical resistivity of the formations, and acoustic, nuclear, etc. measurements.
These measurement and intervention techniques are well known to individuals skilled in the art and will not be described here in further detail.
The present invention is particularly designed for making measurements or interventions in a well producing petroleum effluents, with the well preferably having tubes or drains which delimit its walls.
Patent EP-A-0/256.601 describes, for example, a method and a device for drilling into the ground with the aid of an assembly consisting of two concentric tubes made of metal, rigid and unreeled from a winch by plastic deformation of the material of the tubes.
U.S. Pat. No. 4,685,516 describes a device for measurements or interventions in a well having an instrument disposed at the lower part of a hollow tube initially wound onto a winch which is made to rotate to move the instrument in a well.
The tubes described EP-A-0/256.601 and U.S. Pat. No. 4,685,816 are made of metal and have low flexibility to facilitate movement of the instrument. This flexibility produces plastic deformations upon winding onto the winch or unwinding from the winch. The electrical conductor they may contain is disposed in the hollow cavity inside the tube. In addition to the tube being relatively heavy, a further problem arises in that emplacement a conductor can only be carried out when the tube is wound up.
While Patent FR-B-1,249,236 describes a flexible steel tube usable to drill the ground, a disadvantage of this flexible steel. Tube resides in the fact that it is very expensive to manufacture.
All tubes traditionally used are vulnerable to corrosion and are not particularly suitable for reducing friction with the well wall when the instrument moves, nor even to resist this friction.
The drawbacks of the devices according to the prior art are considerably reduced, if not eliminated, by the use of the device according to the present invention to carry out measurements or interventions in a drilled well, with the device having a rod or shaft connected to a measuring or intervention instrument, disposed at a lower end of the rod.
According to device of the present invention, the rod is, in particular, flexurally elastic and rigid in compression, with the rod having at least one line designed for carrying energy or information such as an electric, fluid, or optical line, and with the rod being constructed so as to be wound onto at least one winch and comprising a composite or polymer non-composite material.
The composite material may be, for example, glass, carbon, or polyaramide fibers such as Kevlar which is a registered trademark of Dupont de Nemours, these fibers being embedded in a thermoplastic or thermosetting resin matrix.
The polymer material without its reinforcing elements may be chosen from the following group of polymers: polyamide, vinylidene polyfluoride, and high-density cross-linked polyethylene.
The rod may be essentially solid and be constructed so as to withstand twisting. When the rod has a neutral fiber along which no tractive or compressive force appears when said rod is flexed, the carrying line may be disposed substantially in the vicinity of the neutral fiber.
The nature of the material of which the outer part of the rod consists may be such so as to decrease friction between the rod and the well wall.
The rod may be made by a continuously producing machine, particularly by extrusion or by pultrusion.
The rod may have several energy or information carrying lines.
The rod may be hollow and the line may be embedded in the thickness of said rod. The outer part of the rod may include an anti-abrasion agent.
The above and other objects, features and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawings which show, for the purpose of illustration only, several embodiments in accordance with the present invention.